It has become a popular destination for large conventions rather than a mecca for individual gamblers and run of the mill tourists. Costs are always higher near large convention centers. The attendees are pretty much locked into using the nearby resources and are willing to pay a higher price for the convenience.
Once you get away from The Strip and Downtown, Las Vegas is almost normal except for the expectation of tipping everywhere.
Next time we go, we're going to get out of town and stay at one of those $40 per night places in either Primm (south on I-15) or Mesquite (north on I-15). The drive isn't long for some healthy $$ savings.